Fri, 20 Mar 2009 23:19:36 -0700
6814659: separable cleanups and subroutines for 6655638
Summary: preparatory but separable changes for method handles
Reviewed-by: kvn, never
1 /*
2 * Copyright 2001-2009 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
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23 */
25 # include "incls/_precompiled.incl"
26 # include "incls/_parallelScavengeHeap.cpp.incl"
28 PSYoungGen* ParallelScavengeHeap::_young_gen = NULL;
29 PSOldGen* ParallelScavengeHeap::_old_gen = NULL;
30 PSPermGen* ParallelScavengeHeap::_perm_gen = NULL;
31 PSAdaptiveSizePolicy* ParallelScavengeHeap::_size_policy = NULL;
32 PSGCAdaptivePolicyCounters* ParallelScavengeHeap::_gc_policy_counters = NULL;
33 ParallelScavengeHeap* ParallelScavengeHeap::_psh = NULL;
34 GCTaskManager* ParallelScavengeHeap::_gc_task_manager = NULL;
36 static void trace_gen_sizes(const char* const str,
37 size_t pg_min, size_t pg_max,
38 size_t og_min, size_t og_max,
39 size_t yg_min, size_t yg_max)
40 {
41 if (TracePageSizes) {
42 tty->print_cr("%s: " SIZE_FORMAT "," SIZE_FORMAT " "
43 SIZE_FORMAT "," SIZE_FORMAT " "
44 SIZE_FORMAT "," SIZE_FORMAT " "
45 SIZE_FORMAT,
46 str, pg_min / K, pg_max / K,
47 og_min / K, og_max / K,
48 yg_min / K, yg_max / K,
49 (pg_max + og_max + yg_max) / K);
50 }
51 }
53 jint ParallelScavengeHeap::initialize() {
54 // Cannot be initialized until after the flags are parsed
55 GenerationSizer flag_parser;
57 size_t yg_min_size = flag_parser.min_young_gen_size();
58 size_t yg_max_size = flag_parser.max_young_gen_size();
59 size_t og_min_size = flag_parser.min_old_gen_size();
60 size_t og_max_size = flag_parser.max_old_gen_size();
61 // Why isn't there a min_perm_gen_size()?
62 size_t pg_min_size = flag_parser.perm_gen_size();
63 size_t pg_max_size = flag_parser.max_perm_gen_size();
65 trace_gen_sizes("ps heap raw",
66 pg_min_size, pg_max_size,
67 og_min_size, og_max_size,
68 yg_min_size, yg_max_size);
70 // The ReservedSpace ctor used below requires that the page size for the perm
71 // gen is <= the page size for the rest of the heap (young + old gens).
72 const size_t og_page_sz = os::page_size_for_region(yg_min_size + og_min_size,
73 yg_max_size + og_max_size,
74 8);
75 const size_t pg_page_sz = MIN2(os::page_size_for_region(pg_min_size,
76 pg_max_size, 16),
77 og_page_sz);
79 const size_t pg_align = set_alignment(_perm_gen_alignment, pg_page_sz);
80 const size_t og_align = set_alignment(_old_gen_alignment, og_page_sz);
81 const size_t yg_align = set_alignment(_young_gen_alignment, og_page_sz);
83 // Update sizes to reflect the selected page size(s).
84 //
85 // NEEDS_CLEANUP. The default TwoGenerationCollectorPolicy uses NewRatio; it
86 // should check UseAdaptiveSizePolicy. Changes from generationSizer could
87 // move to the common code.
88 yg_min_size = align_size_up(yg_min_size, yg_align);
89 yg_max_size = align_size_up(yg_max_size, yg_align);
90 size_t yg_cur_size = align_size_up(flag_parser.young_gen_size(), yg_align);
91 yg_cur_size = MAX2(yg_cur_size, yg_min_size);
93 og_min_size = align_size_up(og_min_size, og_align);
94 og_max_size = align_size_up(og_max_size, og_align);
95 size_t og_cur_size = align_size_up(flag_parser.old_gen_size(), og_align);
96 og_cur_size = MAX2(og_cur_size, og_min_size);
98 pg_min_size = align_size_up(pg_min_size, pg_align);
99 pg_max_size = align_size_up(pg_max_size, pg_align);
100 size_t pg_cur_size = pg_min_size;
102 trace_gen_sizes("ps heap rnd",
103 pg_min_size, pg_max_size,
104 og_min_size, og_max_size,
105 yg_min_size, yg_max_size);
107 const size_t total_reserved = pg_max_size + og_max_size + yg_max_size;
108 char* addr = Universe::preferred_heap_base(total_reserved, Universe::UnscaledNarrowOop);
110 // The main part of the heap (old gen + young gen) can often use a larger page
111 // size than is needed or wanted for the perm gen. Use the "compound
112 // alignment" ReservedSpace ctor to avoid having to use the same page size for
113 // all gens.
115 ReservedHeapSpace heap_rs(pg_max_size, pg_align, og_max_size + yg_max_size,
116 og_align, addr);
118 if (UseCompressedOops) {
119 if (addr != NULL && !heap_rs.is_reserved()) {
120 // Failed to reserve at specified address - the requested memory
121 // region is taken already, for example, by 'java' launcher.
122 // Try again to reserver heap higher.
123 addr = Universe::preferred_heap_base(total_reserved, Universe::ZeroBasedNarrowOop);
124 ReservedHeapSpace heap_rs0(pg_max_size, pg_align, og_max_size + yg_max_size,
125 og_align, addr);
126 if (addr != NULL && !heap_rs0.is_reserved()) {
127 // Failed to reserve at specified address again - give up.
128 addr = Universe::preferred_heap_base(total_reserved, Universe::HeapBasedNarrowOop);
129 assert(addr == NULL, "");
130 ReservedHeapSpace heap_rs1(pg_max_size, pg_align, og_max_size + yg_max_size,
131 og_align, addr);
132 heap_rs = heap_rs1;
133 } else {
134 heap_rs = heap_rs0;
135 }
136 }
137 }
139 os::trace_page_sizes("ps perm", pg_min_size, pg_max_size, pg_page_sz,
140 heap_rs.base(), pg_max_size);
141 os::trace_page_sizes("ps main", og_min_size + yg_min_size,
142 og_max_size + yg_max_size, og_page_sz,
143 heap_rs.base() + pg_max_size,
144 heap_rs.size() - pg_max_size);
145 if (!heap_rs.is_reserved()) {
146 vm_shutdown_during_initialization(
147 "Could not reserve enough space for object heap");
148 return JNI_ENOMEM;
149 }
151 _reserved = MemRegion((HeapWord*)heap_rs.base(),
152 (HeapWord*)(heap_rs.base() + heap_rs.size()));
154 CardTableExtension* const barrier_set = new CardTableExtension(_reserved, 3);
155 _barrier_set = barrier_set;
156 oopDesc::set_bs(_barrier_set);
157 if (_barrier_set == NULL) {
158 vm_shutdown_during_initialization(
159 "Could not reserve enough space for barrier set");
160 return JNI_ENOMEM;
161 }
163 // Initial young gen size is 4 Mb
164 //
165 // XXX - what about flag_parser.young_gen_size()?
166 const size_t init_young_size = align_size_up(4 * M, yg_align);
167 yg_cur_size = MAX2(MIN2(init_young_size, yg_max_size), yg_cur_size);
169 // Split the reserved space into perm gen and the main heap (everything else).
170 // The main heap uses a different alignment.
171 ReservedSpace perm_rs = heap_rs.first_part(pg_max_size);
172 ReservedSpace main_rs = heap_rs.last_part(pg_max_size, og_align);
174 // Make up the generations
175 // Calculate the maximum size that a generation can grow. This
176 // includes growth into the other generation. Note that the
177 // parameter _max_gen_size is kept as the maximum
178 // size of the generation as the boundaries currently stand.
179 // _max_gen_size is still used as that value.
180 double max_gc_pause_sec = ((double) MaxGCPauseMillis)/1000.0;
181 double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;
183 _gens = new AdjoiningGenerations(main_rs,
184 og_cur_size,
185 og_min_size,
186 og_max_size,
187 yg_cur_size,
188 yg_min_size,
189 yg_max_size,
190 yg_align);
192 _old_gen = _gens->old_gen();
193 _young_gen = _gens->young_gen();
195 const size_t eden_capacity = _young_gen->eden_space()->capacity_in_bytes();
196 const size_t old_capacity = _old_gen->capacity_in_bytes();
197 const size_t initial_promo_size = MIN2(eden_capacity, old_capacity);
198 _size_policy =
199 new PSAdaptiveSizePolicy(eden_capacity,
200 initial_promo_size,
201 young_gen()->to_space()->capacity_in_bytes(),
202 intra_heap_alignment(),
203 max_gc_pause_sec,
204 max_gc_minor_pause_sec,
205 GCTimeRatio
206 );
208 _perm_gen = new PSPermGen(perm_rs,
209 pg_align,
210 pg_cur_size,
211 pg_cur_size,
212 pg_max_size,
213 "perm", 2);
215 assert(!UseAdaptiveGCBoundary ||
216 (old_gen()->virtual_space()->high_boundary() ==
217 young_gen()->virtual_space()->low_boundary()),
218 "Boundaries must meet");
219 // initialize the policy counters - 2 collectors, 3 generations
220 _gc_policy_counters =
221 new PSGCAdaptivePolicyCounters("ParScav:MSC", 2, 3, _size_policy);
222 _psh = this;
224 // Set up the GCTaskManager
225 _gc_task_manager = GCTaskManager::create(ParallelGCThreads);
227 if (UseParallelOldGC && !PSParallelCompact::initialize()) {
228 return JNI_ENOMEM;
229 }
231 return JNI_OK;
232 }
234 void ParallelScavengeHeap::post_initialize() {
235 // Need to init the tenuring threshold
236 PSScavenge::initialize();
237 if (UseParallelOldGC) {
238 PSParallelCompact::post_initialize();
239 } else {
240 PSMarkSweep::initialize();
241 }
242 PSPromotionManager::initialize();
243 }
245 void ParallelScavengeHeap::update_counters() {
246 young_gen()->update_counters();
247 old_gen()->update_counters();
248 perm_gen()->update_counters();
249 }
251 size_t ParallelScavengeHeap::capacity() const {
252 size_t value = young_gen()->capacity_in_bytes() + old_gen()->capacity_in_bytes();
253 return value;
254 }
256 size_t ParallelScavengeHeap::used() const {
257 size_t value = young_gen()->used_in_bytes() + old_gen()->used_in_bytes();
258 return value;
259 }
261 bool ParallelScavengeHeap::is_maximal_no_gc() const {
262 return old_gen()->is_maximal_no_gc() && young_gen()->is_maximal_no_gc();
263 }
266 size_t ParallelScavengeHeap::permanent_capacity() const {
267 return perm_gen()->capacity_in_bytes();
268 }
270 size_t ParallelScavengeHeap::permanent_used() const {
271 return perm_gen()->used_in_bytes();
272 }
274 size_t ParallelScavengeHeap::max_capacity() const {
275 size_t estimated = reserved_region().byte_size();
276 estimated -= perm_gen()->reserved().byte_size();
277 if (UseAdaptiveSizePolicy) {
278 estimated -= _size_policy->max_survivor_size(young_gen()->max_size());
279 } else {
280 estimated -= young_gen()->to_space()->capacity_in_bytes();
281 }
282 return MAX2(estimated, capacity());
283 }
285 bool ParallelScavengeHeap::is_in(const void* p) const {
286 if (young_gen()->is_in(p)) {
287 return true;
288 }
290 if (old_gen()->is_in(p)) {
291 return true;
292 }
294 if (perm_gen()->is_in(p)) {
295 return true;
296 }
298 return false;
299 }
301 bool ParallelScavengeHeap::is_in_reserved(const void* p) const {
302 if (young_gen()->is_in_reserved(p)) {
303 return true;
304 }
306 if (old_gen()->is_in_reserved(p)) {
307 return true;
308 }
310 if (perm_gen()->is_in_reserved(p)) {
311 return true;
312 }
314 return false;
315 }
317 // Static method
318 bool ParallelScavengeHeap::is_in_young(oop* p) {
319 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
320 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap,
321 "Must be ParallelScavengeHeap");
323 PSYoungGen* young_gen = heap->young_gen();
325 if (young_gen->is_in_reserved(p)) {
326 return true;
327 }
329 return false;
330 }
332 // Static method
333 bool ParallelScavengeHeap::is_in_old_or_perm(oop* p) {
334 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
335 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap,
336 "Must be ParallelScavengeHeap");
338 PSOldGen* old_gen = heap->old_gen();
339 PSPermGen* perm_gen = heap->perm_gen();
341 if (old_gen->is_in_reserved(p)) {
342 return true;
343 }
345 if (perm_gen->is_in_reserved(p)) {
346 return true;
347 }
349 return false;
350 }
352 // There are two levels of allocation policy here.
353 //
354 // When an allocation request fails, the requesting thread must invoke a VM
355 // operation, transfer control to the VM thread, and await the results of a
356 // garbage collection. That is quite expensive, and we should avoid doing it
357 // multiple times if possible.
358 //
359 // To accomplish this, we have a basic allocation policy, and also a
360 // failed allocation policy.
361 //
362 // The basic allocation policy controls how you allocate memory without
363 // attempting garbage collection. It is okay to grab locks and
364 // expand the heap, if that can be done without coming to a safepoint.
365 // It is likely that the basic allocation policy will not be very
366 // aggressive.
367 //
368 // The failed allocation policy is invoked from the VM thread after
369 // the basic allocation policy is unable to satisfy a mem_allocate
370 // request. This policy needs to cover the entire range of collection,
371 // heap expansion, and out-of-memory conditions. It should make every
372 // attempt to allocate the requested memory.
374 // Basic allocation policy. Should never be called at a safepoint, or
375 // from the VM thread.
376 //
377 // This method must handle cases where many mem_allocate requests fail
378 // simultaneously. When that happens, only one VM operation will succeed,
379 // and the rest will not be executed. For that reason, this method loops
380 // during failed allocation attempts. If the java heap becomes exhausted,
381 // we rely on the size_policy object to force a bail out.
382 HeapWord* ParallelScavengeHeap::mem_allocate(
383 size_t size,
384 bool is_noref,
385 bool is_tlab,
386 bool* gc_overhead_limit_was_exceeded) {
387 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
388 assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
389 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
391 HeapWord* result = young_gen()->allocate(size, is_tlab);
393 uint loop_count = 0;
394 uint gc_count = 0;
396 while (result == NULL) {
397 // We don't want to have multiple collections for a single filled generation.
398 // To prevent this, each thread tracks the total_collections() value, and if
399 // the count has changed, does not do a new collection.
400 //
401 // The collection count must be read only while holding the heap lock. VM
402 // operations also hold the heap lock during collections. There is a lock
403 // contention case where thread A blocks waiting on the Heap_lock, while
404 // thread B is holding it doing a collection. When thread A gets the lock,
405 // the collection count has already changed. To prevent duplicate collections,
406 // The policy MUST attempt allocations during the same period it reads the
407 // total_collections() value!
408 {
409 MutexLocker ml(Heap_lock);
410 gc_count = Universe::heap()->total_collections();
412 result = young_gen()->allocate(size, is_tlab);
414 // (1) If the requested object is too large to easily fit in the
415 // young_gen, or
416 // (2) If GC is locked out via GCLocker, young gen is full and
417 // the need for a GC already signalled to GCLocker (done
418 // at a safepoint),
419 // ... then, rather than force a safepoint and (a potentially futile)
420 // collection (attempt) for each allocation, try allocation directly
421 // in old_gen. For case (2) above, we may in the future allow
422 // TLAB allocation directly in the old gen.
423 if (result != NULL) {
424 return result;
425 }
426 if (!is_tlab &&
427 size >= (young_gen()->eden_space()->capacity_in_words(Thread::current()) / 2)) {
428 result = old_gen()->allocate(size, is_tlab);
429 if (result != NULL) {
430 return result;
431 }
432 }
433 if (GC_locker::is_active_and_needs_gc()) {
434 // GC is locked out. If this is a TLAB allocation,
435 // return NULL; the requestor will retry allocation
436 // of an idividual object at a time.
437 if (is_tlab) {
438 return NULL;
439 }
441 // If this thread is not in a jni critical section, we stall
442 // the requestor until the critical section has cleared and
443 // GC allowed. When the critical section clears, a GC is
444 // initiated by the last thread exiting the critical section; so
445 // we retry the allocation sequence from the beginning of the loop,
446 // rather than causing more, now probably unnecessary, GC attempts.
447 JavaThread* jthr = JavaThread::current();
448 if (!jthr->in_critical()) {
449 MutexUnlocker mul(Heap_lock);
450 GC_locker::stall_until_clear();
451 continue;
452 } else {
453 if (CheckJNICalls) {
454 fatal("Possible deadlock due to allocating while"
455 " in jni critical section");
456 }
457 return NULL;
458 }
459 }
460 }
462 if (result == NULL) {
464 // Exit the loop if if the gc time limit has been exceeded.
465 // The allocation must have failed above (result must be NULL),
466 // and the most recent collection must have exceeded the
467 // gc time limit. Exit the loop so that an out-of-memory
468 // will be thrown (returning a NULL will do that), but
469 // clear gc_time_limit_exceeded so that the next collection
470 // will succeeded if the applications decides to handle the
471 // out-of-memory and tries to go on.
472 *gc_overhead_limit_was_exceeded = size_policy()->gc_time_limit_exceeded();
473 if (size_policy()->gc_time_limit_exceeded()) {
474 size_policy()->set_gc_time_limit_exceeded(false);
475 if (PrintGCDetails && Verbose) {
476 gclog_or_tty->print_cr("ParallelScavengeHeap::mem_allocate: "
477 "return NULL because gc_time_limit_exceeded is set");
478 }
479 return NULL;
480 }
482 // Generate a VM operation
483 VM_ParallelGCFailedAllocation op(size, is_tlab, gc_count);
484 VMThread::execute(&op);
486 // Did the VM operation execute? If so, return the result directly.
487 // This prevents us from looping until time out on requests that can
488 // not be satisfied.
489 if (op.prologue_succeeded()) {
490 assert(Universe::heap()->is_in_or_null(op.result()),
491 "result not in heap");
493 // If GC was locked out during VM operation then retry allocation
494 // and/or stall as necessary.
495 if (op.gc_locked()) {
496 assert(op.result() == NULL, "must be NULL if gc_locked() is true");
497 continue; // retry and/or stall as necessary
498 }
499 // If a NULL result is being returned, an out-of-memory
500 // will be thrown now. Clear the gc_time_limit_exceeded
501 // flag to avoid the following situation.
502 // gc_time_limit_exceeded is set during a collection
503 // the collection fails to return enough space and an OOM is thrown
504 // the next GC is skipped because the gc_time_limit_exceeded
505 // flag is set and another OOM is thrown
506 if (op.result() == NULL) {
507 size_policy()->set_gc_time_limit_exceeded(false);
508 }
509 return op.result();
510 }
511 }
513 // The policy object will prevent us from looping forever. If the
514 // time spent in gc crosses a threshold, we will bail out.
515 loop_count++;
516 if ((result == NULL) && (QueuedAllocationWarningCount > 0) &&
517 (loop_count % QueuedAllocationWarningCount == 0)) {
518 warning("ParallelScavengeHeap::mem_allocate retries %d times \n\t"
519 " size=%d %s", loop_count, size, is_tlab ? "(TLAB)" : "");
520 }
521 }
523 return result;
524 }
526 // Failed allocation policy. Must be called from the VM thread, and
527 // only at a safepoint! Note that this method has policy for allocation
528 // flow, and NOT collection policy. So we do not check for gc collection
529 // time over limit here, that is the responsibility of the heap specific
530 // collection methods. This method decides where to attempt allocations,
531 // and when to attempt collections, but no collection specific policy.
532 HeapWord* ParallelScavengeHeap::failed_mem_allocate(size_t size, bool is_tlab) {
533 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
534 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
535 assert(!Universe::heap()->is_gc_active(), "not reentrant");
536 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
538 size_t mark_sweep_invocation_count = total_invocations();
540 // We assume (and assert!) that an allocation at this point will fail
541 // unless we collect.
543 // First level allocation failure, scavenge and allocate in young gen.
544 GCCauseSetter gccs(this, GCCause::_allocation_failure);
545 PSScavenge::invoke();
546 HeapWord* result = young_gen()->allocate(size, is_tlab);
548 // Second level allocation failure.
549 // Mark sweep and allocate in young generation.
550 if (result == NULL) {
551 // There is some chance the scavenge method decided to invoke mark_sweep.
552 // Don't mark sweep twice if so.
553 if (mark_sweep_invocation_count == total_invocations()) {
554 invoke_full_gc(false);
555 result = young_gen()->allocate(size, is_tlab);
556 }
557 }
559 // Third level allocation failure.
560 // After mark sweep and young generation allocation failure,
561 // allocate in old generation.
562 if (result == NULL && !is_tlab) {
563 result = old_gen()->allocate(size, is_tlab);
564 }
566 // Fourth level allocation failure. We're running out of memory.
567 // More complete mark sweep and allocate in young generation.
568 if (result == NULL) {
569 invoke_full_gc(true);
570 result = young_gen()->allocate(size, is_tlab);
571 }
573 // Fifth level allocation failure.
574 // After more complete mark sweep, allocate in old generation.
575 if (result == NULL && !is_tlab) {
576 result = old_gen()->allocate(size, is_tlab);
577 }
579 return result;
580 }
582 //
583 // This is the policy loop for allocating in the permanent generation.
584 // If the initial allocation fails, we create a vm operation which will
585 // cause a collection.
586 HeapWord* ParallelScavengeHeap::permanent_mem_allocate(size_t size) {
587 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
588 assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
589 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
591 HeapWord* result;
593 uint loop_count = 0;
594 uint gc_count = 0;
595 uint full_gc_count = 0;
597 do {
598 // We don't want to have multiple collections for a single filled generation.
599 // To prevent this, each thread tracks the total_collections() value, and if
600 // the count has changed, does not do a new collection.
601 //
602 // The collection count must be read only while holding the heap lock. VM
603 // operations also hold the heap lock during collections. There is a lock
604 // contention case where thread A blocks waiting on the Heap_lock, while
605 // thread B is holding it doing a collection. When thread A gets the lock,
606 // the collection count has already changed. To prevent duplicate collections,
607 // The policy MUST attempt allocations during the same period it reads the
608 // total_collections() value!
609 {
610 MutexLocker ml(Heap_lock);
611 gc_count = Universe::heap()->total_collections();
612 full_gc_count = Universe::heap()->total_full_collections();
614 result = perm_gen()->allocate_permanent(size);
616 if (result != NULL) {
617 return result;
618 }
620 if (GC_locker::is_active_and_needs_gc()) {
621 // If this thread is not in a jni critical section, we stall
622 // the requestor until the critical section has cleared and
623 // GC allowed. When the critical section clears, a GC is
624 // initiated by the last thread exiting the critical section; so
625 // we retry the allocation sequence from the beginning of the loop,
626 // rather than causing more, now probably unnecessary, GC attempts.
627 JavaThread* jthr = JavaThread::current();
628 if (!jthr->in_critical()) {
629 MutexUnlocker mul(Heap_lock);
630 GC_locker::stall_until_clear();
631 continue;
632 } else {
633 if (CheckJNICalls) {
634 fatal("Possible deadlock due to allocating while"
635 " in jni critical section");
636 }
637 return NULL;
638 }
639 }
640 }
642 if (result == NULL) {
644 // Exit the loop if the gc time limit has been exceeded.
645 // The allocation must have failed above (result must be NULL),
646 // and the most recent collection must have exceeded the
647 // gc time limit. Exit the loop so that an out-of-memory
648 // will be thrown (returning a NULL will do that), but
649 // clear gc_time_limit_exceeded so that the next collection
650 // will succeeded if the applications decides to handle the
651 // out-of-memory and tries to go on.
652 if (size_policy()->gc_time_limit_exceeded()) {
653 size_policy()->set_gc_time_limit_exceeded(false);
654 if (PrintGCDetails && Verbose) {
655 gclog_or_tty->print_cr("ParallelScavengeHeap::permanent_mem_allocate: "
656 "return NULL because gc_time_limit_exceeded is set");
657 }
658 assert(result == NULL, "Allocation did not fail");
659 return NULL;
660 }
662 // Generate a VM operation
663 VM_ParallelGCFailedPermanentAllocation op(size, gc_count, full_gc_count);
664 VMThread::execute(&op);
666 // Did the VM operation execute? If so, return the result directly.
667 // This prevents us from looping until time out on requests that can
668 // not be satisfied.
669 if (op.prologue_succeeded()) {
670 assert(Universe::heap()->is_in_permanent_or_null(op.result()),
671 "result not in heap");
672 // If GC was locked out during VM operation then retry allocation
673 // and/or stall as necessary.
674 if (op.gc_locked()) {
675 assert(op.result() == NULL, "must be NULL if gc_locked() is true");
676 continue; // retry and/or stall as necessary
677 }
678 // If a NULL results is being returned, an out-of-memory
679 // will be thrown now. Clear the gc_time_limit_exceeded
680 // flag to avoid the following situation.
681 // gc_time_limit_exceeded is set during a collection
682 // the collection fails to return enough space and an OOM is thrown
683 // the next GC is skipped because the gc_time_limit_exceeded
684 // flag is set and another OOM is thrown
685 if (op.result() == NULL) {
686 size_policy()->set_gc_time_limit_exceeded(false);
687 }
688 return op.result();
689 }
690 }
692 // The policy object will prevent us from looping forever. If the
693 // time spent in gc crosses a threshold, we will bail out.
694 loop_count++;
695 if ((QueuedAllocationWarningCount > 0) &&
696 (loop_count % QueuedAllocationWarningCount == 0)) {
697 warning("ParallelScavengeHeap::permanent_mem_allocate retries %d times \n\t"
698 " size=%d", loop_count, size);
699 }
700 } while (result == NULL);
702 return result;
703 }
705 //
706 // This is the policy code for permanent allocations which have failed
707 // and require a collection. Note that just as in failed_mem_allocate,
708 // we do not set collection policy, only where & when to allocate and
709 // collect.
710 HeapWord* ParallelScavengeHeap::failed_permanent_mem_allocate(size_t size) {
711 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
712 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
713 assert(!Universe::heap()->is_gc_active(), "not reentrant");
714 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
715 assert(size > perm_gen()->free_in_words(), "Allocation should fail");
717 // We assume (and assert!) that an allocation at this point will fail
718 // unless we collect.
720 // First level allocation failure. Mark-sweep and allocate in perm gen.
721 GCCauseSetter gccs(this, GCCause::_allocation_failure);
722 invoke_full_gc(false);
723 HeapWord* result = perm_gen()->allocate_permanent(size);
725 // Second level allocation failure. We're running out of memory.
726 if (result == NULL) {
727 invoke_full_gc(true);
728 result = perm_gen()->allocate_permanent(size);
729 }
731 return result;
732 }
734 void ParallelScavengeHeap::ensure_parsability(bool retire_tlabs) {
735 CollectedHeap::ensure_parsability(retire_tlabs);
736 young_gen()->eden_space()->ensure_parsability();
737 }
739 size_t ParallelScavengeHeap::unsafe_max_alloc() {
740 return young_gen()->eden_space()->free_in_bytes();
741 }
743 size_t ParallelScavengeHeap::tlab_capacity(Thread* thr) const {
744 return young_gen()->eden_space()->tlab_capacity(thr);
745 }
747 size_t ParallelScavengeHeap::unsafe_max_tlab_alloc(Thread* thr) const {
748 return young_gen()->eden_space()->unsafe_max_tlab_alloc(thr);
749 }
751 HeapWord* ParallelScavengeHeap::allocate_new_tlab(size_t size) {
752 return young_gen()->allocate(size, true);
753 }
755 void ParallelScavengeHeap::fill_all_tlabs(bool retire) {
756 CollectedHeap::fill_all_tlabs(retire);
757 }
759 void ParallelScavengeHeap::accumulate_statistics_all_tlabs() {
760 CollectedHeap::accumulate_statistics_all_tlabs();
761 }
763 void ParallelScavengeHeap::resize_all_tlabs() {
764 CollectedHeap::resize_all_tlabs();
765 }
767 // This method is used by System.gc() and JVMTI.
768 void ParallelScavengeHeap::collect(GCCause::Cause cause) {
769 assert(!Heap_lock->owned_by_self(),
770 "this thread should not own the Heap_lock");
772 unsigned int gc_count = 0;
773 unsigned int full_gc_count = 0;
774 {
775 MutexLocker ml(Heap_lock);
776 // This value is guarded by the Heap_lock
777 gc_count = Universe::heap()->total_collections();
778 full_gc_count = Universe::heap()->total_full_collections();
779 }
781 VM_ParallelGCSystemGC op(gc_count, full_gc_count, cause);
782 VMThread::execute(&op);
783 }
785 // This interface assumes that it's being called by the
786 // vm thread. It collects the heap assuming that the
787 // heap lock is already held and that we are executing in
788 // the context of the vm thread.
789 void ParallelScavengeHeap::collect_as_vm_thread(GCCause::Cause cause) {
790 assert(Thread::current()->is_VM_thread(), "Precondition#1");
791 assert(Heap_lock->is_locked(), "Precondition#2");
792 GCCauseSetter gcs(this, cause);
793 switch (cause) {
794 case GCCause::_heap_inspection:
795 case GCCause::_heap_dump: {
796 HandleMark hm;
797 invoke_full_gc(false);
798 break;
799 }
800 default: // XXX FIX ME
801 ShouldNotReachHere();
802 }
803 }
806 void ParallelScavengeHeap::oop_iterate(OopClosure* cl) {
807 Unimplemented();
808 }
810 void ParallelScavengeHeap::object_iterate(ObjectClosure* cl) {
811 young_gen()->object_iterate(cl);
812 old_gen()->object_iterate(cl);
813 perm_gen()->object_iterate(cl);
814 }
816 void ParallelScavengeHeap::permanent_oop_iterate(OopClosure* cl) {
817 Unimplemented();
818 }
820 void ParallelScavengeHeap::permanent_object_iterate(ObjectClosure* cl) {
821 perm_gen()->object_iterate(cl);
822 }
824 HeapWord* ParallelScavengeHeap::block_start(const void* addr) const {
825 if (young_gen()->is_in_reserved(addr)) {
826 assert(young_gen()->is_in(addr),
827 "addr should be in allocated part of young gen");
828 if (Debugging) return NULL; // called from find() in debug.cpp
829 Unimplemented();
830 } else if (old_gen()->is_in_reserved(addr)) {
831 assert(old_gen()->is_in(addr),
832 "addr should be in allocated part of old gen");
833 return old_gen()->start_array()->object_start((HeapWord*)addr);
834 } else if (perm_gen()->is_in_reserved(addr)) {
835 assert(perm_gen()->is_in(addr),
836 "addr should be in allocated part of perm gen");
837 return perm_gen()->start_array()->object_start((HeapWord*)addr);
838 }
839 return 0;
840 }
842 size_t ParallelScavengeHeap::block_size(const HeapWord* addr) const {
843 return oop(addr)->size();
844 }
846 bool ParallelScavengeHeap::block_is_obj(const HeapWord* addr) const {
847 return block_start(addr) == addr;
848 }
850 jlong ParallelScavengeHeap::millis_since_last_gc() {
851 return UseParallelOldGC ?
852 PSParallelCompact::millis_since_last_gc() :
853 PSMarkSweep::millis_since_last_gc();
854 }
856 void ParallelScavengeHeap::prepare_for_verify() {
857 ensure_parsability(false); // no need to retire TLABs for verification
858 }
860 void ParallelScavengeHeap::print() const { print_on(tty); }
862 void ParallelScavengeHeap::print_on(outputStream* st) const {
863 young_gen()->print_on(st);
864 old_gen()->print_on(st);
865 perm_gen()->print_on(st);
866 }
868 void ParallelScavengeHeap::gc_threads_do(ThreadClosure* tc) const {
869 PSScavenge::gc_task_manager()->threads_do(tc);
870 }
872 void ParallelScavengeHeap::print_gc_threads_on(outputStream* st) const {
873 PSScavenge::gc_task_manager()->print_threads_on(st);
874 }
876 void ParallelScavengeHeap::print_tracing_info() const {
877 if (TraceGen0Time) {
878 double time = PSScavenge::accumulated_time()->seconds();
879 tty->print_cr("[Accumulated GC generation 0 time %3.7f secs]", time);
880 }
881 if (TraceGen1Time) {
882 double time = PSMarkSweep::accumulated_time()->seconds();
883 tty->print_cr("[Accumulated GC generation 1 time %3.7f secs]", time);
884 }
885 }
888 void ParallelScavengeHeap::verify(bool allow_dirty, bool silent) {
889 // Why do we need the total_collections()-filter below?
890 if (total_collections() > 0) {
891 if (!silent) {
892 gclog_or_tty->print("permanent ");
893 }
894 perm_gen()->verify(allow_dirty);
896 if (!silent) {
897 gclog_or_tty->print("tenured ");
898 }
899 old_gen()->verify(allow_dirty);
901 if (!silent) {
902 gclog_or_tty->print("eden ");
903 }
904 young_gen()->verify(allow_dirty);
905 }
906 if (!silent) {
907 gclog_or_tty->print("ref_proc ");
908 }
909 ReferenceProcessor::verify();
910 }
912 void ParallelScavengeHeap::print_heap_change(size_t prev_used) {
913 if (PrintGCDetails && Verbose) {
914 gclog_or_tty->print(" " SIZE_FORMAT
915 "->" SIZE_FORMAT
916 "(" SIZE_FORMAT ")",
917 prev_used, used(), capacity());
918 } else {
919 gclog_or_tty->print(" " SIZE_FORMAT "K"
920 "->" SIZE_FORMAT "K"
921 "(" SIZE_FORMAT "K)",
922 prev_used / K, used() / K, capacity() / K);
923 }
924 }
926 ParallelScavengeHeap* ParallelScavengeHeap::heap() {
927 assert(_psh != NULL, "Uninitialized access to ParallelScavengeHeap::heap()");
928 assert(_psh->kind() == CollectedHeap::ParallelScavengeHeap, "not a parallel scavenge heap");
929 return _psh;
930 }
932 // Before delegating the resize to the young generation,
933 // the reserved space for the young and old generations
934 // may be changed to accomodate the desired resize.
935 void ParallelScavengeHeap::resize_young_gen(size_t eden_size,
936 size_t survivor_size) {
937 if (UseAdaptiveGCBoundary) {
938 if (size_policy()->bytes_absorbed_from_eden() != 0) {
939 size_policy()->reset_bytes_absorbed_from_eden();
940 return; // The generation changed size already.
941 }
942 gens()->adjust_boundary_for_young_gen_needs(eden_size, survivor_size);
943 }
945 // Delegate the resize to the generation.
946 _young_gen->resize(eden_size, survivor_size);
947 }
949 // Before delegating the resize to the old generation,
950 // the reserved space for the young and old generations
951 // may be changed to accomodate the desired resize.
952 void ParallelScavengeHeap::resize_old_gen(size_t desired_free_space) {
953 if (UseAdaptiveGCBoundary) {
954 if (size_policy()->bytes_absorbed_from_eden() != 0) {
955 size_policy()->reset_bytes_absorbed_from_eden();
956 return; // The generation changed size already.
957 }
958 gens()->adjust_boundary_for_old_gen_needs(desired_free_space);
959 }
961 // Delegate the resize to the generation.
962 _old_gen->resize(desired_free_space);
963 }
965 #ifndef PRODUCT
966 void ParallelScavengeHeap::record_gen_tops_before_GC() {
967 if (ZapUnusedHeapArea) {
968 young_gen()->record_spaces_top();
969 old_gen()->record_spaces_top();
970 perm_gen()->record_spaces_top();
971 }
972 }
974 void ParallelScavengeHeap::gen_mangle_unused_area() {
975 if (ZapUnusedHeapArea) {
976 young_gen()->eden_space()->mangle_unused_area();
977 young_gen()->to_space()->mangle_unused_area();
978 young_gen()->from_space()->mangle_unused_area();
979 old_gen()->object_space()->mangle_unused_area();
980 perm_gen()->object_space()->mangle_unused_area();
981 }
982 }
983 #endif